Welcome to the forum.
The procedure to fill the transmission requires that the transmission is warmed up, then filled to the drain level with the engine running. Make sure it was done properly.
Here's the parts catalog from ZF. The fill procedure is included around page 7:
https://aftermarket.zf.com/remotemedia/pdfc-media/pdfc-files/pdfc-usa-4/pdfc-5hp19flporsche.pdf
Here's a clip of what it says:
I have done this on a Boxster and a Cayenne. I do not like being under a running vehicle while it is in gear. Take precautions.
